This is a low effort take that depends on the ambiguity of language to sound true.
"Drain" for the author apparently means literally using up a finite amount of human energy, concentration, and willpower. That's a truism.
"Drain" for an introvert can mean anything from starting a muscle tension clock that will eventually cause a headache to a straight-up panic attack that could take hours/days to recover from.
It's probably even worse for young people who are introverts and haven't been taught how to say no or set boundaries. (I remember explaining to some college-age people that saying no is a skill, and they looked at me like I had just revealed to them that, with enough practice, humans can actually fly.)